Seat adjusting mechanism



Nov. 4, 1958 L. P. GARVEY E L SEAT ADJUSTING MECHANISM Original FiledFeb. 27, 1956 3 Sheets-Sheet 1 INVENTORS (Yam d5 S'emzg BY 01184? 'aqz z-fif ll 1 4* ATT ORNEY Nov. 4, 1958 L. P. GARVEY ETAL 2,858,378

SEAT ADJUSTING MECHANISM I Original Filed Feb. 27, 1956 5 Sheets-Sheet 2Q 1%. QP N w R E ATTORNEY Nov. 4, v 1958 L. P. GARYEY ET AL SEATADJUSTING MECHANISM Original Filed Feb. 27, 1956 5 Sheets-Sheet 3INVENTORS CZazzqi' Kemazg 011252942154 T TORNEY SEAT ADJUSTING MECHANISMLouis P. Garvey and Clautl S. Semar, Birmingham, Micl 1., assignors toGeneral Motors Corporation, Detroit, Mich., a corporation of Delaware567,839, February Continuation of application Serial No.

1957, Serial No.

27, 1956. This application May 29, 663,571

8 Claims. (Cl. 15514) This invention relates to seat adjustingmechanisms and more particularly to a vehicle seat adjusting mechanismwhich will adjust the seat in both horizontal and vertical directions.This application is a continuation of our copending application S. N.567,839 filed February 27, 1956, now abandoned.

The seat adjusting mechanism of this invention is of the toggle linkagetype and includes spaced pairs of pivotally interconnected upper andlower support members at each side of the seat, with the upper membersof each pair being pivoted to the seat and the lower members of eachpair being pivoted to a fixed support and interconnectedby a shiftablelink. By swinging the upper support members of both spaced pairsrelative to the lower support members thereof, the seat may be adjustedin horizontal directions regardless of its vertical position and byswinging the lower support members of both spaced pairs relative to thefixed support the seat may be adjusted in vertical directions regardlessof its horizontal position.

One of the particular disadvantages often found in this type of seatadjusting mechanism is rocking or instability in both horizontal andvertical directions. There is an inherent tendency for the pivots of thesupport members to become worn after periods of use so that the supportmembers may shift relative to each other in any position of the seat.Thus one side of the seat may shift horizontally forwardly or rearwardlyrelative to the other side of the seat to cause horizontal instabilityor rocking, or one side of the seat may shift vertically upwardly ordownwardly relative to the other side of the seat to cause verticalinstability or rocking. Another disadvantage often found in this type ofseat adjusting mechanism is seat side sway or shifting movement of theseat laterally of the vehicle. This also results after periods of usewhen the pivots of the support members have become worn. Thesedisadvantages have often discouraged commercial usage of this type ofseat adjusting mechanism since the entire seat adjusting mechanism mustoften be replaced when the various pivots have become worn.

This invention in its preferred embodiment, recognizes the particulardisadvantages of this type of seat adjusting mechanism and provides anovel and unique manner of solving the problems of horizontal andvertical instability and seat side sway and yet provides a linkage typeseat adjusting mechanism which retains the advantages of such mechanismsover other types of seat adjusting mechanisms. In addition, the linkagetype seat adjusting mechanism of this invention is power operated formovement selectively and alternately in both horizontal and verticaldirections.

An object of this invention is to provide a new and improved seatadjusting mechanism which will adjust a vehicle seat in both horizontaland vertical directions. Another object of this invention is to providea new and improved seat adjusting mechanism which will selectively A2,858,878 Patented Nov. 4, 1958 and alternately adjust a vehicle seat inhorizontal and vertical directions. A further object of this inventionis to provide a vehicle seat adjusting mechanism of the toggle linkagetype which will selectively and alternately adjust the vehicle seattions and which reduces rocking or instability in both horizontal andvertical directions to a minimum. A more specific object of thisinvention is to provide a vehicle seat adjusting mechanism of the togglelinkage type which will selectively and alternately adjust a vehicleseat in horizontal and vertical directions and which includes togglelinkage structure of double construction at the rear of the seat andtoggle linkage structure of single construction at the front of the seatwith opposite front toggle linkage structures being interconnected byequalizer rods.

These and other objects of this invention will be readily apparent fromthe following specification and drawings, in which:

Figure 1 is a plan view of a portion of the seat adjusting mechanism ofthis invention;

Figure 2 is a side elevational view of the seat adjusting mechanism ofthis invention, with parts being broken away for clarity ofillustration;

Figure 3 is a sectional view taken on the plane indicated by line 3-3 ofFigure 2; and

Figure 4 is a sectional view taken on the plane indicated by line 4-4 ofFigure 2.

Before proceeding with the description of the seat adjusting mechanismit will be understood that the mechanism is the same on either side ofthe seat, although of different hand. Therefore, only one such adjustingmechanism will'be described.

Referring now to Figures 2, 3, and 4 of the drawings, a U-shaped bracket10 adjacent the rear of the seat includes inboard and outboard legs 14and 16 respectively joined by webs 20 which are secured to the vehiclefloor pan 22 to rigidly mount the brackets on the body. The inboard leg14 is apertured at 24 and the outboard leg 16 is apertured at 26. AU-shaped vertical adjusting bracket 28 includes inboard and outboardlegs 30 and 32 respectively joined by a web 34. The inboard leg 30 isapertured at 36, 38, and 40 and the outboard leg 32 is apertured at 42and 44. A headed stud 46 secured within aperture 40 of the inboard leg30 includes a tapered portion 48 received within aperture 24 of theinboard leg 14 of bracket 10. An apertured concave spring washer 50fitting on the cylindrical terminal portion of the stud is secured inplace against leg 14 of bracket 10 by a retaining ring 54. The springwasher and tapered portion 48 of stud 46 operate to take up lateralthrusts tending to separate bracket 28 from bracket 10.

A headed stud 56 secured Within aperture 26 of the outboard leg 16 ofbracket 10 includes a tapered portion 58 receiving aperture 44 of theoutboard leg 32 of bracket 28. An apertured concave spring washer 60fitting on the terminal cylindrical portion of stud 56 is secured inplace against leg 32 of bracket 28 by a retaining ring 64. The springwasher 60 and tapered portion 58 of stud 56 operate to take up lateralthrusts tending to separate bracket 28 from bracket 10. Studs 46 and 56thus pro.- vide a pivotal axis of swinging for bracket 28 on bracket 10and also cooperate with spring washers 50 and 60 to take up lateralthrusts tending to separate bracket 28 from bracket 10.

A U-shaped horizontal adjusting bracket 66 includes inboard and outboardlegs 68 and 70 respectively joined by a web 72. The inboard leg 68 isapertured at 72 and 74, and the outboard leg 70 is apertured at 76and 78A headed stud 80 secured within aperture 38 of the inboard leg 30 ofbracket 28 includes a tapered portion: 82

in horizontal and vertical direc-' separate the brackets.

A headed stud 90 secured within aperture 76 of the outboard leg 70 ofbracket 66 includes a tapered portion 92 received within aperture 42 ofthe outboard leg 32 of bracket 28. An apertured concave spring washer 94fitting on the cylindrical terminal portion of stud 90 is retained inplace against leg 32 of bracket 28 by a retaining ring 98. The springwasher 94 and tapered portion 92 of stud 90 operate to take up lateralthrusts tending to separate the brackets. Studs 80 and 98 thus provide apivotal axis of swinging for bracket 66 on bracket 28 and also cooperatewith spring washers 84 and 94 to take up lateral thrusts tending toseparate the brackets.

A pair of offset brackets 100 are bolted at 102 to the side walls of theseat fran e channel side member 103. The upper ends of brackets 191) areapertured at 104 and headed studs 106 are secured within the apertures.Studs 186 include tapered portions 108 received within apertures 74 and78 in the inboard and outboard legs 68 and 70, respectively, of bracket66. An apertured concave spring Washer 111 fits on the cylindricalterminal portion of each stud and is secured in place by a retainingring 114. The spring washers 110 and tapered portions 168 of studs 106cooperate to take up any lateral thrusts tending to separate brackets100 from bracket 66, and studs 106 also provide a pivotal aXis or"swinging of brackets 106 on bracket 66. The flanges 116 of the seatframe channel side members are apertured at 118 to allow for assembly ofbrackets 1130 and swinging movement of bracket 66 relative to brackets100.

Brackets 28, 66, and 106 support the rear portion of each of the seatframe channel side members for both horizontal and vertical adjustment.If brackets 28 are moved clockwise about their pivotal axis of swingingdefined by studs 46 and 56, brackets 66 will be shifted upwardly andwill swing about their pivotal axis of swinging defined by studs 80 and90 to raise the rear portion of the seat by means of studs 186 asbrackets 66 and 104) swing relative to each other about the pivotal axisof swinging defined by studs 166. Similarly, if brackets 28 are movedcounterclockwise about their pivotal axis of swinging defined by studs46 and 56, brackets 66 will be shifted downwardly and will swing abouttheir pivotal axis of swinging defined by studs 86 and 90 to lower therear portion of the seat by means of studs 106 as brackets 66 and 106swing relative to each other about the pivotal axis of swinging definedby studs 106. The latter movement of the rear portion of the seat isindicated schematically in Figure 2 by dot and dash lines.

If brackets 66 are moved clockwise about their pivotal axis of swingingdefined by studs 80 and 9t) and brackets 28 are held stationary, therear portion of the seat will be moved horizontally rearwardly asbrackets 100 are shifted rearwardly by means of studs 166 and brackets66 and 100 swing relative to each other about the axis of swingingdefined by studs 1116. Similarly, if brackets 66 are movedcounterclockwise about their pivotal axis of swinging defined by studs80 and 90 and brackets 28 are held stationary, the rear portion of theseat will be moved horizontally forwardly as brackets 100 are shiftedforwardly by means of studs 166 and brackets 66 and 100 swing relativeto each other about the pivotal axis defined by studs 106. Thus, it canbe seen that the rear portion of each of the seat frame channel sidemembers is supported on the vehicle floor pan for both horizontal andvertical adi s m A headed stud 120 secured within aperture 36 of theinboard leg of bracket 28 includes a tapered portion 122 which receivesan aperture 124 in the rear end of a shiftable link 126. An aperturedconcave spring washer 128 fitting on the cylindrical terminal portion ofstud is secured in place against link 126 by a retaining ring 132. Thespring washer and tapered portion 122 of stud 120 operate to take uplateral thrusts tending to separate link 126 and bracket 28, and thestud also provides a pivotal axis of swinging of the link relative tothe bracket.

An angular bracket 134 secured to the vehicle floor pan 22 adjacent theforward portion of the seat includes an aperture 136. An offset verticaladjusting plate 138 includes apertures 140, 142, and 144. A headed stud146 is secured within aperture 141 and includes a tapered portion 148received within aperture 136 of bracket 134. An apertured concave springwasher 150 is secured on the cylindrical terminal portion of stud 146against bracket 134 by a retaining ring 154. The spring Washer 150 andtapered portion 148 of stud 146 operate to take up lateral thruststending to separate plate 138 from bracket 134, and the stud alsoprovides a pivotal axis of swinging of the plate on the bracket. Aheaded stud 156 secured within aperture 142 of plate 138 includes atapered portion 158 which receives an aperture 160 in the forward end oflink 126. An apertured concave spring washer 162 fitting on thecylindrical terminal portion of stud 156 is secured in place againstlink 126 by a retaining ring 166. The spring washer 162 and taperedportion 158 of stud 156 operate to take up lateral thrusts tending toseparate the link and the plate, and the stud also provides a pivotalaxis of swinging of the link relative to the plate.

An offset arm 168 is apertured at 176 at the lower end thereof, and aheaded stud 172 is secured within the aperture. The stud includes atapered portion 174- which is received within aperture 14-1 of plate138. An apertured concave spring washer 176 fitting on the cylindricalterminal portion of stud 172 is secured in place against plate 138 by aretaining ring 181). The spring washer 176 and tapered portion 174 ofstud 172 operate to take up lateral thrusts tending to separate arm 168and plate 138, and the stud also provides a pivotal axis of swinging ofthe arm relative to the plate. The upper end of arm 168 is apertured at182 and a headed stud 184 secured within the aperture includes a taperedportion 186. An offset bracket 188 welded or otherwise secured to thebase of the forward portion of the seat frame channel side member 103includes an aperture 196 which receives the tapered portion 186 of stud184. An apertured concave spring washer 192 fitting on the cylindricalterminal portion of stud 184 is secured in place against-bracket 188 bya retaining ring 196. The spring washer 192 and tapered portion 186 ofstud 184 operate to take up lateral thrusts tending to separate bracket188 and arm 168, and the stud also provides a pivotal axis of swingingof the arm on the bracket.

Plate 138, arm 168, and bracket 18% support the forward portion of theseat frame channel side frame members for both horizontal and verticaladjustment. If plates 138 are moved clockwise about their pivotal axisof swinging defined by studs 146, arms will be shifted upwardly and willswing about their pivotal axis of swinging defined by studs 172 to raisethe forward portion of the seat by means of studs 18 1 as brackets andarms 168 swing relative to each other about the pivotal axis of swingingdefined by studs 184. Similarly, if plates 138 are movedcounterclockwise about their pivotal axis of swinging defined by studs146, arms 163 will be shifted downwardly and will swing about theirpivotal axis of swinging defined by studs 172 to lower the forward portion of the seat by means of studs 184 as arms 168 and brackets 188swing relative to each other about the pivotal axis of swinging definedby studs 184-. This latter movement is indicated schematically by dotand dash lines in Figure 2.

Since plates 138 and brackets 28 are interconnected by the shiftablelinks 126, each must swing in the same same direction. Thus, clockwiseswinging of plates 188 and brackets 28 will result in the entire seatbeing raised,

- and counterclockwise swinging of the plates and brackets will resultin the entire seat being lowered. Thus, both sides of the seat will beraised or lowered at the same time depending on the direction ofswinging of plate 138 and brackets 28. V v

If arms 168 are moved clockwise about their pivotal axis of swingingdefined by studs 172 and plates 138 are held stationary, the forwardportion of the seat will be moved horizontally rearwardly as brackets188 are shifted rearwardly by means of studs 184 and arms 168 andbrackets 188 swing relative to each other about the axis of swingingdefined by these studs. Similarly, if arms 168 are movedcounterclockwise about their pivotal axis of swinging defined by studs172 and plates 138 are held stationary, the forward portion of the seatwill be moved horizontally forwardly as brackets 188 are shiftedforwardly by means of studs 148 and arms 168 and brackets 188 swingrelative to each other about the axis of swinging defined by thesestuds. Since the seat frame channel side members 103 are connected toboth arms 168 and brackets 66, the entire seat will be movedhorizontally forwardly or rearwardly depending on the direction ofswinging of the arms and brackets. No shiftable interconnection such aslink 126 is needed between the arms and brackets since the seat framechannel side members perform the function of a shiftable interconnectionto provide for horizontal movement of the entire seat.

In order to ensure that both sides ofthe seat are raised and lowered anequal distance upon swinging movement of plates 138 and brackets 28, avertical equalizer rod 198 spans the seat and is. secured at the endsthereof to an opposite pair of plates 138. Since plates 138 areinterconnected with brackets 28 by means of the shiftable links 126, noequalizer rod is needed between brackets 28. Likewise, to ensure thatboth sides of the seat are moved horizontally forwardly and rearwardlyan equal distance, a horizontal equalizer rod 200 spans the seat and issecured at the ends thereof to the headed studs 184 on arms 168 as shownparticularly in Figure 3. Since both equalizer rods are located adjacentthe forward edge of the seat, additional foot room is provided for rearseat passengers.

Referring now particularly to Figure l of the drawings, a motor drivenscrew jack 202 is pivoted at 204 at one end thereof to a bracket 206which is secured to the vehicle floor pan 22 at 208. The other end ofscrew jack 202 is pivoted at 210 to an angular bracket212 which iswelded or otherwise secured to the vertical torque rod 198. Pivots 204and 210 are of the same construction and, therefore, only pivot 204 willbe particularly described. Pivot 204 includes a stud 214 havingcylindrical portions 216 and 218 joined by a tapered portion 220, andtapered portion 222 which terminates in a threaded portion 224. A nut226 is threaded on portion 224 to rigidly secure stud 214 to bracket206. The screw jack 202 is provided with an aperture of the same shapeas portions 216, 218, and. 222 of the stud and a conical spiral spring230 fits between bracket 206 and the screw jack to continually urge theaperture in the screw jack into tight fitting engagement with stud 214.Thus, the stud and the conical spring Washer operate to take up playbetween the screw jack and bracket 206 and resist lateral thrust tendingto move these members toward each other.

A motor driven screw jack 232 is pivoted at 234 at one end thereof to abracket 236 which is secured to the vehicle floor pan 22 at 238. Theother end of the screw jack 232 is pivoted at 240 to an angular bracket242 which is secured to the seat frame front channel member 244 whichspans the front portion of the seat and is secured at the ends thereofto the forward ends of the seat frame side channel members 103. A seatframe rear channel member (not shown) spans the seat at the rear edgethereof and is secured to the rear ends of the seat frame channel sidemembers to provide a rigid seat frame.

Upon extension and retraction of screw jack 202 it can be seen that theseat will be adjusted to various vertical positions as the plate members138 and brackets 28 swing about their pivotal supports on the vehiclefloor pan as previously described. Upon extension of screw jack 202,plates 138 are shifted counterclockwise about the pivotal axis ofswinging defined by studs 146 and brackets 28 are moved in the samedirection about the pivotal axis of swinging defined by studs 46 and 56to lower the seat.

Similarly, upon retraction of screw jack 202 the seat will be raised asplates 138 and brackets 28 swing in an opposite direction about theirrespective pivotal axes of swing- Screw jack 232 operates directlyagainst the seat frame rather than operating against the horizontaltorque rod 200. Upon extension of screw jack 232 the entire seat framewill be moved horizontally forwardly as arms 168 swing about theirpivotal axis of swinging defined by studs 172 and brackets 66 swingabout their pivotal axis of swinging defined by studs and as previouslydescribed. Similarly, upon retraction of screw jack 232 the seat will bemoved horizontally rearwardly as arms 168 and brackets 66 swing in anopposite direction about their respective pivotal axes of swinging.

It will be noted that the seat may be adjusted vertically regardless ofthe horizontal position of the seat and likewise that the seat may beadjusted horizontally regardless of the vertical position of the seat.When the seat has been moved to the desired vertical position screw jack202 operates as a fixed link pivotally interconnecting the vehicle floorpan and the vertical torque rod 198 to prevent any movement of thevertical torque rod and plates 138 about the pivotal axis of swingingdefined by studs 146. Thus, the seat will be securely held in anyvertical position but may be adjusted horizontally regardless of thisposition since arms 168 and brackets 66 may swing relative to plates 138and brackets 28.

When the seat has been moved to a horizontally adjusted position screwjack 232 operates in the same manner as screw jack 202 to function as afixed link interconnecting the vehicle floor pan and the seat frame.Thus, the seat is rigidly held in any horizontally adjusted positionalthough it may be adjusted vertically in any such position by swingingmovement of plates 138 and bracket 28 as previously described. Screwjack 232 is pivoted to both the seat and the floor pan and thus willallow swinging movement of the seat frame about an axis defined by pivot234 to allow vertical adjustment of the seat upon actuation of screwjack 202.

Since most of the weight of the occupant is centered at the rear of theseat frame, bracket 28 and 66 are of double construction although theyfunction as a single toggle linkage. By providing such a doubleconstruction together with the lateral take up feature of the pairs ofaligned spaced studs at each side of the seat which define the variouspivotal axes of swinging of the rear support members, horizontal andvertical rocking or instability and seat side sway are reduced to aminimum. Each pair of aligned spaced studs, such as studs 46, 56; 80,90; 106; have their tapered portions extending oppositely with respectto each other to insure that the studs and spring washers will act toresist any displacement of the support members relatively to each otheronce the seat has been adjusted to any horizontal or vertical position.The forward support members for the seat also function as a togglelinkage but are of single construction rather than double construction.The single pivots on each side of the seat at the front portion thereofalso have their tapered portions extending oppositely with respect toeach other to further insure adequate and effective take up. Thehorizontal and vertical equalizer rods which span the seat adjacent thefront edge thereof impart further rigidity to the seat and supportmembers and also cooperate With the lateral take up features of thestuds of these. support members to prevent displacement of' the supportmembers relative to each other.

Thus, this invention provides a seat adjusting mechanism which willimpart both horizontal and vertical movement to a vehicle seat and whichincludes a minimum number of parts for ease of assembly and maintenance.The seat adjusting mechanism includes a number of pivotallyinterconnected front and rear support members and the pivots whichinterconnect these support members include a lateral take up feature toreduce horizontal and vertical rocking or instability to a minimum andprovide a substantially stationary seat support in any adjusted positionof the seat. The horizontal and vertical equalizer rods adjacent thefront edge of the seat also aid the pivots of the front support membersin providing a stationary seat support.

While a specific embodiment of this invention has been shown, anddescribed, various changes and modifications may be made within thescope and spirit of this invention.

We claim:

1. In combination with a vehicle seat, a seat adjusting mechanismcomprising, a fixed support, toggle linkage means extending between saidsupport and said seat adjacent each side thereof, said linkage meansincluding lower link means pivotally mounted on said fixed support andupper link means pivotally secured to said seat, first means operable tomove said toggle link means relative to said support to move said seatto vertical adjusted positions, second means operable to move said upperlink means relative to said lower link means to move said seat tohorizontal adjusted positions, and lateral thrust take up means at thepivots of each of said link means.

2. In combination with a vehicle seat, a seat adjusting mechanismcomprising, a fixed support, toggle linkage means extending between saidsupport and said seat adjacent each side thereof, said linkage meansincluding lower link means pivotally mounted on said fixed support andupper link means pivotally secured to said seat, drive means connectingopposite pairs of upper links for conjoint rotation thereof relative tosaid lower links to move said seat to horizontal adjusted positions,means operable to move said toggle linkage means, relative to said fixedsupport to move said seat to vertical adjusted positions, and lateralthrust take up means at the pivots of each of said link means.

v3. In combination with a vehicle seat, a seat adjusting mechanismcomprising, a fixed support, toggle linkage means extending between saidsupport and said seat adjacent each side thereof, said linkage meansincluding lower link means pivotally mounted on said fixed support andupper link means pivotally secured to said seat, first drive meansconnecting opposite pairs of upper links for conjoint rotation thereofrelative to said lower links to move said seat to horizontal adjustedpositions, second drive means connecting opposite pairs of lower linksfor conjoint rotation thereof relative to said fixed support to movesaid seat to vertical adjusted positions, and lateral thrust take upmeans at the pivots of each of said link means.

4. In combination with a vehicle seat, a seat adjusting mechanismcomprising, a fixed support, spaced toggle linkage means extendingbetween said support and said seat adjacent each side thereof, saidlinkage means including lower link means pivotally mounted on said fixedsupport and upper link means pivotally secured to said seat, first drivemeans connecting the upper links of opposite toggle linkage means ateach side of said seat for conjoint rotation thereof relative to saidlower links to move said seat to horizontal adjusted positions, seconddrive means concans extending between said support and said seatadjacent each side thereof, said linkage means including lower linkmeans pivotally mounted on said fixed support and upper link meanspivotally secured to said seat, first; means operable to move saidtoggle link means relative to said support to move said seat to verticaladjusted positions, and second means operable to move said upper linkmeans relative to said lower link means to move said seat to horizontaladjusted positions.

6. In combination with a vehicle seat, a seat adjusting A mechanismcomprising, a fixed support, toggle linkage means extending between saidsupport and said seat adjacent each side thereof, said linkage meansincluding lower link means pivotally mounted on said fixed support andupper link means pivotally secured to said seat, drive means connectingopposite pairs of upper links for conjoint rotation thereof relative tosaid lower links to move said seat to horizontal adjusted positions, andmeans operable to move said toggle linkage means relative to said,

fixed support to move said seat to vertical adjusted positions.

7. In combination with a vehicle seat, a seat adjusting mechanismcomprising, a fixed support, toggle linkage means extending between saidsuppoit and said seat adjacent each side thereof, said linkage meanincluding lower link means pivotally mounted on said fixed support andupper link means pivotally secured to said seat, first drive meansconnecting opposite pairs of upper links for conjoint rotation thereofrelative to said lower links to move said seat to horizontal adjustedpositions, and second drive means connecting opposite pairs of lowerlinks for conjoint rotation thereof relative to said fixed support tomove said seat to vertical adjusted positions.

8. In combination with a vehicle seat, a seatadjusting mechanismcomprising, a fixed support, spaced toggle linkage means extendingbetween said support and said seat adjacent each side thereof, saidlinkage means including lower link means pivotally mounted on said firstsupport and upper link means pivotally secured to said seat, first drivemeans connecting the upper links of opposite toggle linkage means ateach side of said seat for conjoint rotation thereof relative to saidlower links to move'said seat to horizontal adjusted positions, seconddrive means connecting the lower links of said opposite toggle linkagemeans forconjoint rotation thereof relative to said support to move saidseat to vertical adjusted positions, and means interconnecting saidlower link means of each of said spaced toggle linkage means forconjoint rotation of said lower link means at each side'of said seat.

References Cited in the file of this patent UNITED STATES PATENTS2,161,366 McGregor June 6, 1939 2,260,032 Kaiser et al. Oct. 21, 19412,555,804 McCarthy June 5, 1951 FOREIGN PATENTS 551,808 Great BritainMar. 10, 1943

